> Anyone know if FLTK lends itself nicely to being SWIG'ed to Ruby?

I don't know, but I believe that the pyFLTK project (the Python language
binding for FLTK) uses SWIG to generate its wrapper code, and if so, one
might be able to use their SWIG interface files as a starting point or,
better yet, coordinate with them so that all of the code is developed
together. The home page for pyFLTK is:

    http://pyfltk.sourceforge.net/

Hope this helps,

Lyle